Moderate drug use and delay discounting: A comparison of heavy, light, and never smokers.

Abstract

Delay discounting was examined in light smokers (10 or fewer cigarettes per day) and compared with previously published delay discounting data for heavy and never smokers. Participants evaluated several hypothetical outcomes: money gains and loses ($10, $100, and $1,000), health gains and losses (durations of improved and impoverished health subjectively equivalent to $1,000), cigarette gains and losses (amounts subjectively equivalent to $1,000), and potentially real rewards ($10 and $100). Light smokers discounted money significantly more than never smokers, but light smokers did not differ from heavy smokers. The 3 groups did not statistically differ in discounting of health consequences. Similarly, the 2 smoking groups were not found to differ in discounting of cigarettes. Like heavy smokers, light smokers discounted cigarettes significantly more than money and health. Several significant, positive correlations were found between smoking rate and various discounting measures in the heavy smokers but not in the light smokers. Several previous findings were replicated, helping to validate the present results: the sign effect (greater discounting of gains than losses), the magnitude effect (greater discounting of smaller rewards), reliability of discounting measures over time, and the consistency of hypothetical and potentially real rewards. These data suggest that even moderate levels of drug use may be associated with high delay discounting levels.

Delay discounting: Concepts and measures.

“…Richards, Zhang, Mitchell, & de Wit (1999) reduced the number of attempts required to estimate the indifference points from an amount adjustment procedure (i.e., to at least 74 and at most 103), which was reproduced in later studies (Baker et al, 2003;Johnson et al, 2007). Starting with a fixed delayed amount, two upper limits (maximum and minimum) and two lower limits (maximum and minimum) were always established for the changes, which changed according to the previous choices of the subjects.…”

“…Typical studies offer the choice alternatives in series with determined delays and amounts of money. Such studies usually present five (Patak & Reynolds, 2007), seven (Johnson, Bickel, & Baker, 2007;Myerson et al, 2003), or eight delays (Gonçalves, 2005;Myerson & Green, 1995) that can begin with 6 h (Robles & Vargas, 2008) or 1 day (Johnson et al, 2007) and reach 25 years (Gonçalves, 2005;Johnson et al, 2007;Robles & Vargas, 2008). The amounts can start at $1 (Green et al, 1996) or $10 (Johnson et al, 2007) and end at $100 (Odum & Rainaud, 2003), $1,000 (Robles & Vargas, 2008), or $10,000 (Green et al, 1996), with a total of 25 (Odum & Rainaud, 2003), 27 (Bickel, Odum, & Madden, 1999;Ohmura et al, 2006), or 30 amounts (Gonçalves, 2005), depending on the objectives of the study.…”

Testing the Reliability of Delay Discounting of Ten Commodities Using the Fill-in-the-Blank Method

“…A second goal was to extend the measure of reliability beyond hypothetical monetary amounts. A number of researchers (e.g., Chapman, 1996;Hardisty & Weber, 2009;Johnson, Bickel, & Baker, 2007) have examined whether individuals display a single, general rate of discounting or whether their rates of discounting differ across commodities. Several investigations have shown that there are absolute differences in the rates of discounting of different commodities, although it is sometimes difficult to determine whether these differences represent differences between commodities themselves or whether the results are confounded by differences in the magnitude of the commodities presented to the participants (see Hardisty & Weber, 2009, for a more detailed discussion).…”

Is there an impatience genotype leading to non-adherence to long-term therapies?

“…It is therefore possible to quantify the level of impulsivity of human individuals: some are more impatient, which means that people discount the future to a greater or lesser extent [13]. This level of impulsivity is associated with some pathogenic behaviours; the k value of the hyperbolic function describing impulsivity during a monetary choice has been found to be higher in different forms of addiction (smoking [14], alcohol habits [15], addictions to various kinds of drugs [16]), and, recently, in depressive patients [17] and obese women [18].…”